>> Step 1:
>
>>*snip*
>
>> Step 3:
>
> Slight concern- aren't you actually here giving us a solution to a
> problem, and then just asking to implement the algorithm you've
> already explained? Where's the fun in that.
>
> Part of the joy should be in doing some research and applying some
> thought to find the best algorithm. It slightly ruins it if you give
> us an answer in the problem.

Well, A* is a _dreadful_ algorithm for route finding, so there's plenty
of scope for finding a way better approach :) Field Guidance, Ho!